From ff68cb626cfac2bae419091a240bedcd1734ff59 Mon Sep 17 00:00:00 2001
From: vng <viktor.govako@gmail.com>
Date: Wed, 29 May 2013 20:08:30 +0300
Subject: [PATCH] Handle file i/o errors according to manuals.

---
 coding/internal/file_data.cpp | 62 +++++++++++++++++++----------------
 coding/internal/file_data.hpp |  3 +-
 2 files changed, 36 insertions(+), 29 deletions(-)

diff --git a/coding/internal/file_data.cpp b/coding/internal/file_data.cpp
index 9c0f7ec864..64e82cacde 100644
--- a/coding/internal/file_data.cpp
+++ b/coding/internal/file_data.cpp
@@ -30,17 +30,14 @@ FileData::FileData(string const & fileName, Op op)
     return;
 #else
   m_File = fopen(fileName.c_str(), modes[op]);
-  if (m_File && ferror(m_File) == 0)
+  if (m_File)
     return;
 
   if (op == OP_WRITE_EXISTING)
   {
     // Special case, since "r+b" fails if file doesn't exist.
-    if (m_File)
-      fclose(m_File);
-
     m_File = fopen(fileName.c_str(), "wb");
-    if (m_File && ferror(m_File) == 0)
+    if (m_File)
       return;
   }
 #endif
@@ -55,9 +52,10 @@ FileData::FileData(string const & fileName, Op op)
 FileData::~FileData()
 {
 #ifndef OMIM_OS_BADA
-  if (0 != fclose(m_File))
+  if (m_File)
   {
-    LOG(LWARNING, ("Error closing file", GetErrorProlog()));
+    if (fclose(m_File))
+      LOG(LWARNING, ("Error closing file", GetErrorProlog()));
   }
 #endif
 }
@@ -76,6 +74,8 @@ string FileData::GetErrorProlog() const
   return m_FileName + "; " + s + "; " + strerror(errno);
 }
 
+static int64_t const INVALID_POS = -1;
+
 uint64_t FileData::Size() const
 {
 #ifdef OMIM_OS_BADA
@@ -85,19 +85,22 @@ uint64_t FileData::Size() const
     MYTHROW(Reader::SizeException, (m_FileName, m_Op, error));
   return attr.GetFileSize();
 #else
-  uint64_t const pos = ftell64(m_File);
-  if (ferror(m_File))
+  int64_t const pos = ftell64(m_File);
+  if (pos == INVALID_POS)
     MYTHROW(Reader::SizeException, (GetErrorProlog(), pos));
-  fseek64(m_File, 0, SEEK_END);
-  if (ferror(m_File))
+
+  if (fseek64(m_File, 0, SEEK_END))
     MYTHROW(Reader::SizeException, (GetErrorProlog()));
-  uint64_t const size = ftell64(m_File);
-  if (ferror(m_File))
+
+  int64_t const size = ftell64(m_File);
+  if (size == INVALID_POS)
     MYTHROW(Reader::SizeException, (GetErrorProlog(), size));
-  fseek64(m_File, pos, SEEK_SET);
-  if (ferror(m_File))
+
+  if (fseek64(m_File, pos, SEEK_SET))
     MYTHROW(Reader::SizeException, (GetErrorProlog(), pos));
-  return size;
+
+  ASSERT_GREATER_OR_EQUAL(size, 0, ());
+  return static_cast<uint64_t>(size);
 #endif
 }
 
@@ -112,9 +115,9 @@ void FileData::Read(uint64_t pos, void * p, size_t size)
   if (static_cast<size_t>(bytesRead) != size || IsFailed(error))
     MYTHROW(Reader::ReadException, (m_FileName, m_Op, error, bytesRead, pos, size));
 #else
-  fseek64(m_File, pos, SEEK_SET);
-  if (ferror(m_File))
+  if (fseek64(m_File, pos, SEEK_SET))
     MYTHROW(Reader::ReadException, (GetErrorProlog(), pos));
+
   size_t const bytesRead = fread(p, 1, size, m_File);
   if (bytesRead != size || ferror(m_File))
     MYTHROW(Reader::ReadException, (GetErrorProlog(), bytesRead, pos, size));
@@ -130,10 +133,12 @@ uint64_t FileData::Pos() const
     MYTHROW(Writer::PosException, (m_FileName, m_Op, error, pos));
   return pos;
 #else
-  uint64_t const result = ftell64(m_File);
-  if (ferror(m_File))
-    MYTHROW(Writer::PosException, (GetErrorProlog(), result));
-  return result;
+  int64_t const pos = ftell64(m_File);
+  if (pos == INVALID_POS)
+    MYTHROW(Writer::PosException, (GetErrorProlog(), pos));
+
+  ASSERT_GREATER_OR_EQUAL(pos, 0, ());
+  return static_cast<uint64_t>(pos);
 #endif
 }
 
@@ -145,8 +150,7 @@ void FileData::Seek(uint64_t pos)
   if (IsFailed(error))
     MYTHROW(Writer::SeekException, (m_FileName, m_Op, error, pos));
 #else
-  fseek64(m_File, pos, SEEK_SET);
-  if (ferror(m_File))
+  if (fseek64(m_File, pos, SEEK_SET))
     MYTHROW(Writer::SeekException, (GetErrorProlog(), pos));
 #endif
 }
@@ -171,8 +175,7 @@ void FileData::Flush()
   if (IsFailed(error))
     MYTHROW(Writer::WriteException, (m_FileName, m_Op, error));
 #else
-  fflush(m_File);
-  if (ferror(m_File))
+  if (fflush(m_File))
     MYTHROW(Writer::WriteException, (GetErrorProlog()));
 #endif
 }
@@ -180,10 +183,13 @@ void FileData::Flush()
 void FileData::Truncate(uint64_t sz)
 {
 #ifdef OMIM_OS_WINDOWS
-  _chsize(fileno(m_File), sz);
+  int const res = _chsize(fileno(m_File), sz);
 #else
-  ftruncate(fileno(m_File), sz);
+  int const res = ftruncate(fileno(m_File), sz);
 #endif
+
+  if (res)
+    MYTHROW(Writer::WriteException, (GetErrorProlog(), sz));
 }
 
 bool GetFileSize(string const & fName, uint64_t & sz)
diff --git a/coding/internal/file_data.hpp b/coding/internal/file_data.hpp
index 1b1cbfa1c1..8c6c3085f1 100644
--- a/coding/internal/file_data.hpp
+++ b/coding/internal/file_data.hpp
@@ -15,7 +15,8 @@ namespace my {
 class FileData
 {
 public:
-  enum Op { OP_READ = 0, OP_WRITE_TRUNCATE = 1, OP_WRITE_EXISTING = 2, OP_APPEND};
+  /// @note Do not change order (@see FileData::FileData).
+  enum Op { OP_READ = 0, OP_WRITE_TRUNCATE, OP_WRITE_EXISTING, OP_APPEND };
 
   FileData(string const & fileName, Op op);
   ~FileData();